Automated data storage libraries are known for providing cost effective storage and retrieval of large quantities of data. The data in automated data storage libraries is stored on data storage media that are, in turn, stored on storage shelves or the like inside the library in a fashion that renders the media, and its resident data, accessible for physical retrieval. Such media is commonly termed “removable media.” Data storage media may comprise any type of media on which data may be stored and which may serve as removable media, including but not limited to magnetic media (such as magnetic tape or disks), optical media (such as optical tape or disks), electronic media (such as PROM, EEPROM, flash PROM, Compactflash™, Smartmedia™, Memory Stick™, etc.), or other suitable media. Typically, the data stored in automated data storage libraries is resident on data storage media that is contained within a cartridge and referred to as a data storage media cartridge. An example of a data storage media cartridge that is widely employed in automated data storage libraries for mass data storage is a magnetic tape cartridge.
In addition to data storage media, automated data storage libraries typically contain data storage drives that store data to, and/or retrieve data from, the data storage media. The transport of data storage media between data storage shelves and data storage drives is typically accomplished by one or more robotic accessors (hereinafter termed “accessors”). Such accessors have grippers for physically retrieving the selected data storage media from the storage shelves within the automated data storage library and transport such media to the data storage drives by moving in the horizontal “X” and vertical “Y” directions. As such, it is important that accessors have the capability of being able to accurately locate storage shelves and data storage drives.
Currently, automated data storage libraries use an optical system such as a barcode scanner reading cartridge barcode labels to perform an inventory of the library. An inventory process is necessary for the library when cartridges are loaded or unloaded from the library, a library door is opened, or the library is powered cycled. The current process for the inventory of the library is relatively slow because the robotics inside the library must drive a barcode reader to scan each cartridge label within the desired area to be inventoried. This slow performance of library inventory can affect overall library performance seen by the client, especially in light of clients' desires for bulk loading and unloading of the library. Thus, there is a need for a quicker inventory method of the automated data storage library.
Another problem with the current inventory process is that each cartridge label must be visible to the barcode reader in order to complete the inventory. If cartridges are stacked behind each other in deep slots, the barcode label of the rear cartridge(s) cannot be read by the barcode scanner. An inventory process could be implemented where the front cartridges in a deep slot are removed so that the barcode labels of the rear cartridges could be read by the barcode scanner, but this would be an extremely slow process due to all of the extra cartridge handling involved. Thus, this is a further need for an efficient inventory method involving deep cartridge storage slots.